Hydroponics sounds great on paper. Until you see the sludge they feed the plants with. Given the incentive to cut costs, especially where it's hard to see and/or measure, not sure I want to get anywhere close to the resulting produce.
This objection baffles me. Traditional agriculture has used literal feces to "feed" plants since its inception, and frequently uses bones and blood as nutrient input. I'm eating the resulting food, not the rot and excrement used to feed it.
That is a fault of imagination ;) Think "processed oil refinery sludge" or some other such industrial horror. Oh, sure, there is a shit ton of heavy metals and/or who knows what other garbage in there, but it's below the FDA limit (hello VW wink wink), so let's roll with it straight to mass human consumption.
What do you mean by "sludge"? Typical hydroponic solution just looks like water, thus the name. The fertilizers used are higher purity ("greenhouse grade", "ultra-soluble", etc.) than those applied to soil, since impurities risk clogging the fertigation equipment.